1. Field of the Invention
The present invention relates to an image pickup apparatus including a light receiving unit and a light emitting unit.
2. Description of the Related Art
Recently, a three-dimensional (3D) television has been released for home use and interest in a 3D video picture has been growing. The 3D image is produced by shooting an object with two image pickup apparatuses which are arranged side-by side, and utilizing the parallax of these shot images. At this time, in order to shoot a 3D image which does not give uncomfortable feeling to users, it is necessary to shoot the moving image while synchronizing shutters between two image pickup apparatuses. Therefore, conventionally, two mage pickup apparatuses are connected with a cable and shooting is performed while sending a synchronization signal from one apparatus to another. However, when the connection is made by the cable, an operation of attaching/detaching the cable is very complicated and gives heavy burden to workers. Therefore, to improve operability, it is conceivable to connect two image pickup apparatuses using optical communication, which does not need the cable connection operation.
On the other hand, a recent image pickup apparatus has employed a light emitting unit for projecting auxiliary light to an object in order to obtain a bright picture even in a dark place. Further, in order to remotely control an image pickup apparatus, the image pickup apparatus may have a remote control system. This system is generally operated using optical communication, and has a light receiving unit in the image pickup apparatus side. Further, to protect elements in both the light emitting unit and the light receiving unit, Japanese Patent Application Laid-Open No. 2000-89095 discusses a technique in which front faces of these units are covered with window members and this technique has been generally used.
However, The light emitting unit is provided to illuminate an object and the light receiving unit in the remote control system is provided to operate the image pickup apparatus from the distant position in a state in which a photographer is within an angle of view. Therefore, in the conventional image pickup apparatus, the light emitting unit and the light receiving unit are arranged to face only the front of the image pickup apparatus. From this configuration, the aforementioned light emitting unit and light receiving unit cannot be used as the communication unit in the state in which two image pickup apparatuses are arranged in parallel, so that the exclusive light emitting unit and light receiving unit need to be provided. This configuration is costly and not practical. Accordingly, in the image pickup apparatus using the conventional technique, it is required to connect between the image pickup apparatuses by a cable to send and receive a synchronization signal, so that the system has a structure which is very complicated to operate and not easily usable.